This mid-career retrospective of the fifty-year-old German artist, best known for his ephebic strain of expressionism, transforms part of the museum’s sixth floor into a gauze-lined attic, strewn with objects including (but not limited to) paintings, childhood drawings, glazed ceramics, ballet slippers, couches, dolls, effigies, and a stack of art works wrapped in brown paper. Althoff emerged from the hothouse of nineteen-nineties Cologne, and the sardonic figurative painting that was in fashion there influenced his images of triangle-nosed miscreants and lovers lost in space; several later paintings (made after the artist moved to Brooklyn) depict Hasidic Jews, among them two jocular men with payot and tzitzit. Althoff has always flitted between mediums, and alongside his sensitive drawings of grandes dames and tender boys (indebted to the Symbolist tradition of Munch and Puvis de Chavannes) are papier-mâché ghouls passed out at a dinner table, an instrumental audio track, and the pumped-in aroma of oud. What unites Althoff’s works is a quality of evanescence, down to the artist-designed catalogue (whose lead essay is written by a Chabad Lubavitch rabbi), which is wrapped in delicate vellum. This is a Gesamtkunstwerk on the cusp of collapse, and it’s that fragility, more than Althoff’s often wearying sentimentality, that makes the exhibition so moving.